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Core Intermediate

07 Ownership

The heart of Rust. These functions take ownership when they shouldn't -- borrow instead, so the caller keeps its values.

Step 1 / 3

Fix total_len so it borrows the vec and the caller can still use it.

Hints

Passing by value moves; borrow with &[T] to read.
The check calls total_len(&v) -- match that.

07_ownership.rs

// Must NOT take ownership -- the caller uses the vec afterward.
fn total_len(items: Vec<String>) -> usize {
    items.iter().map(|s| s.len()).sum()
}

// Must NOT take ownership -- the caller uses the vec afterward.
fn total_len(items: Vec<String>) -> usize {
    items.iter().map(|s| s.len()).sum()
}

Reset to starterCompiled in a sandbox; hidden checks must pass.

Reveal solution

fn total_len(items: &[String]) -> usize {
    items.iter().map(|s| s.len()).sum()
}

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07 Ownership